Replication job leaves multiple open snapshots on target hosts. When an attempt is made to delete (i.e. consolidate) the open snapshots, the vCenter or Host machine returns the error <unable to remove file xxxxxxxxxxxxxxxx as it is locked>. Thus, snapshots keep building up on the VMFS, but can never be deleted. Powering-off the VM has no effect, nor does vMotioning the VM to another host.
This can happen after a failed vRanger 5.2.x VA replication (ESXi only). The target VA has its disks/snapshots in a persistent locked state and does not release the lock as it should after the failed replication job is "rolled-back".
The only way to release the lock on the target VM's disks is to POWER OFF the target VA (powering off the vRanger server/VM has no effect). Once powered off, the standard "Add a new snapshot/Delete All" way of removing orphaned snapshots works, and the VMFS can be cleaned-up.